In this paper we consider the role of standards as a means for interoperability among members of different communities. If we consider, in particular, the healthcare domain, there is an increasing number of efforts to develop explicit and formal representations of medical concepts so as to provide a common infrastructure for the reuse of clinical information and for the integration and the sharing of medical knowledge across the world. A critical issue raises when local customizations of standards are used as standards. If this occurs, standards are no more able to guarantee their supportive function to interoperability. To overcome this problem we propose a solution aiming at making members of different facilities aware of the changes occurred locally in a standard. At architectural level, we propose to build a layer that acts upon the interface of the application by which the articulation of activities across organizational boundaries is mediated (e.g., an handing over between different healthcare facilities). At application level, we provide practitioners with a common visual notation allowing them enrich the artifacts that mediate inter-articulation, by means of a reference to a standard, e.g. a schema of intervention. We claim that this increased awareness can support different people in aligning practices with standards and making standards effective means for coordination and interoperability. Furthermore, we report a case focusing on such a layer and visual notation by which to enrich the interface of the information system that mediates the handingover between an Emergency Service and a hospital emergency department.